Activating MS Authenticator for MS365

Hello, is anyone familiar on how to reactivate MS365 Authenticator on new iPhone?  I recently changed iPhones and my old authenticator did not transfer over.  I have my login credentials but can't fully login as I don't have the two step authentication.  I have been trying to get assistance from Microsoft support, but they keep hanging up on me.  I would appreciate some assistance with this issue, thanks in advance.